The conventional double-ended wrench sets on the market typically include at least two double-ended wrenches in each set. For example, FIG. 1 shows a double-ended wrench set sold by STANLEY, a well-known US company, whose trademark STANLEY is also shown in the drawing. This double-ended wrench set includes fourteen double-ended wrenches 50, each having a wrench body 51 of a different length. The two ends of each wrench body 51 are provided with an opened opening 53 and an enclosed opening 54 respectively, wherein the two openings are of different specifications (e.g., hexagonal or box/ring-shaped) or sizes (e.g., with a diameter of ⅜, 7/16, ½, 9/16, ⅝, 11/16, ¾, 13/16, ⅞, 15/16, 1, 1 1/16, 1⅛, or 1¼ inches). Each opened opening 53 is configured for gripping two sides of a bolt or nut of the corresponding specification and size, while each enclosed opening 54 is designed to be placed around the periphery of a bolt or nut of the corresponding specification and size. The openings 53 and 54 at the two ends of each double-ended wrench 50 are different in specification or size from those of any another double-ended wrench 50. Moreover, the wrench bodies 51 of the double-ended wrenches 50 vary in length, depending on the sizes of the openings 53 and 54 of each double-ended wrench 50. The larger the openings 53 and 54 of each double-ended wrench 50 are, the longer the wrench body 51 will be.
With continued reference to FIG. 1, when the user inserts the fourteen double-ended wrenches 50 into a tool bag 60 and lays the tool bag 60 open on a workbench, the bag must occupy a significant area of the workbench. When rolled and tied up, the tool bag 60 is still quite bulky, let alone heavy, and therefore cannot be carried around with ease. In particular, the widely different lengths of the wrench bodies 51 of the double-ended wrenches 50 result in an asymmetric and distorted bundle once the tool bag 60 is rolled and tied, making it even more difficult to carry the loaded bag around.
Hence, the issue to be addressed by the present invention is to design a double-ended wrench set which not only occupies much less space than its prior art counterparts, but also has a symmetric, compact, and space-saving overall structure to facilitate storage, carrying, and display.